Early watercolor sketches for four of the illustrations that later appeared as engravings in the second edition of John Matthews's book, A Voyage to the River Sierra-Leone, on the Coast of Africa; Containing an Account of the Trade and Productions of the Country, and of the Civil and Religious Customs and Manners of the People (London, 1791). The design for three of the illustrations is attributed to "Lieut. J.M." (likely John Matthews), and a fourth to "Lieut. J. Larcom." Most are also signed "William Porter" on the opposite edge. The watercolors are painted over with lacquer, and there are notations in the margins.